3dB is how much the volume increases when you double the power. When you double the speakers the volume goes up by 6dB. But that is only if the two speakers are right next to each other. If they are separated you will get less than that, probably around 4-5dB, as I said already.Originally Posted by GirgleMirt
Adding a third speaker will add another 1-2dB which is how you get 5-7dB.